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911.
Synopsis Fathead minnow embryos (Pimephales promelas Rafinesque) of 5 different developmental ages (5, 33, 48, 72 and 96 hrs after fertilization) were used as controls and exposed for 2 hrs to a solution of 0.25 Ci ml–1 of3H-Uridine. Another set of embryos (5, 33, 48, 72 and 96 hrs after fertilization) were subjected to the same treatment except that during the one hour immediately preceding the3H-Uridine incubation, the control embryos were placed in water while the experimental embryos were placed in water containing 15 ppm 11.2 LAS. In both cases, radiation counts minute–1 embryo–1 and per milligram of embryo increased over the 4 day developmental period. The embryos with LAS treatment displayed lower radiation counts at all ages as compared to controls, indicating an inhibition of diffusion and uptake of3H-Uridine and/or RNA synthesis. The possible mechanism of LAS is discussed. 相似文献
912.
Using the paper disc-agar plate method, a number of fatty and related acids have been tested for tested activity for inhibiting the growth of Chlorella pyrenoidosa Chick. Of the saturated acids, a peak in growth inhibiting activity wax observed in the C7–C12 range, where inhibition wax observed when solutions down to 0.02 M were applied to the discs. Most of the unsaturated acids tested showed greater inhibition than did the corresponding saturated acids. Acrylic acid showed detectable inhibition at 0.001 M concentration. 相似文献
913.
Contrasting roles of tau and microtubule-associated protein 2 in the vinblastine-induced aggregation of brain tubulin 总被引:2,自引:0,他引:2
R F Ludue?a A Fellous L McManus M A Jordan J Nunez 《The Journal of biological chemistry》1984,259(20):12890-12898
Two different proteins, tau and microtubule-associated protein 2 (MAP 2), are able to stimulate tubulin polymerization into microtubules in vitro, but it is not certain if both proteins act by the same mechanism. We have examined the effects of tau and MAP 2 on the vinblastine-induced polymerization of tubulin into spiral filaments. In the presence of tau, vinblastine induced extensive aggregation of tubulin as shown by a large increase in turbidity. The increase in turbidity was accompanied by the formation of large numbers of spirals composed of a filament 40-60 A in diameter. The rate and extent of this aggregation into spirals were dependent on the concentrations of tubulin, tau, and vinblastine. Unlike normal microtubule assembly, this type of aggregation was not inhibited by colchicine or podophyllotoxin. In contrast, MAP 2, even at high concentrations, was less effective than tau at promoting the vinblastine-induced increase in turbidity of tubulin. In fact, MAP 2 strongly inhibited the effect of tau. These results indicate that tau and MAP 2 interact differently with the tubulin molecule in the presence of vinblastine and suggest that the two proteins may play different roles in regulating or promoting microtubule assembly. Vinblastine may thus be a useful probe in analyzing the modes of interactions of tau and MAP 2 with tubulin. 相似文献
914.
Janire De-La-Torre Guillermo Quindós Cristina Marcos-Arias Xabier Marichalar-Mendia María Luisa Gainza Elena Eraso Amelia Acha-Sagredo José Manuel Aguirre-Urizar 《Revista iberoamericana de micología》2018,35(3):134-139
Background
Candida can be implicated in the pathology of chronic periodontitis.Aims
To analyze the oral Candida carriage in patients suffering from chronic periodontitis (CP) and its correlation with the severity of this condition.Methods
Microbiological samples were taken from 155 patients using the oral rinse (OR) technique and by using paper points in the periodontal pockets (GPP). These patients were divided into 3 groups: 89 patients without CP (control), 47 with moderate CP, and 19 with severe CP. Samples were cultured in a Candida chromogenic agar for Candida. Species were identified by microbiological and molecular methods.Results
Candida was isolated in the OR of 45 (50.6%), 21 (44.7%), and 11 (57.9%) patients, respectively, and in the GPP of 32 (36%), 14 (29.2%), and 10 (42.6%) patients from the control, moderate CP and severe CP groups, respectively. Candida was isolated more frequently and in a greater burden in OR than in GPP (p < 0.01). Candida albicans was the most prevalent species. GPP of patients with CP had poor fungal biodiversity (p < 0.01).Conclusions
Colonization by Candida was present in the samples of patients without CP, and with both moderate and severe CP. Nonetheless, patients with severe CP had a higher rate of Candida colonization, especially by C. albicans. 相似文献915.
Vélez Debora E. Mestre-Cordero Victoria E. Hermann Romina Perego Juliana Harriet Sofia Fernandez-Pazos María de las Mercedes Mourglia Julieta Marina-Prendes M. Gabriela 《Journal of physiology and biochemistry》2020,76(1):85-98
Journal of Physiology and Biochemistry - The cardioprotective activity of rosuvastatin (R) is yet to be known. The objective of this study was to research whether R perfusion before global ischemia... 相似文献
916.
917.
Modig C Olsson PE Barasoain I de Ines C Andreu JM Roach MC Ludueña RF Wallin M 《Cell motility and the cytoskeleton》1999,42(4):315-330
Isolated microtubule proteins from the Atlantic cod (Gadus morhua) assemble at temperatures between 8 and 30 degrees C. The cold-adaptation is an intrinsic property of the tubulin molecules, but the reason for it is unknown. To increase our knowledge of tubulin diversity and its role in cold-adaptation we have further characterized cod tubulins using alpha- and beta-tubulin site-directed antibodies and antibodies towards posttranslationally modified tubulin. In addition, one cod brain beta-tubulin isotype has been sequenced. In mammals there are five beta-tubulins (betaI, betaII, betaIII, betaIVa and betaIVb) expressed in brain. A cod betaIII-tubulin was identified by its electrophoretic mobility after reduction and carboxymethylation. The betaIII-like tubulin accounted for more than 30% of total brain beta-tubulins, the highest yield yet observed in any animal. This tubulin corresponds most probably with an additional band, designated beta(x), which was found between alpha- and beta-tubulins on SDS-polyacrylamide gels. It was found to be phosphorylated and neurospecific, and constituted about 30% of total cod beta-tubulin isoforms. The sequenced cod tubulin was identified as a betaIV-tubulin, and a betaIV-isotype was stained by a C-terminal specific antibody. The amount of staining indicates that this isotype, as in mammals, only accounts for a minor part of the total brain beta-tubulin. Based on the estimated amounts of betaIII- and betaIV-tubulins in cod brain, our results indicate that cod has at least one additional beta-tubulin isotype and that beta-tubulin diversity evolved early during fish evolution. The sequenced cod betaIV-tubulin had four unique amino acid substitutions when compared to beta-tubulin sequences from other animals, while one substitution was in common with Antarctic rockcod beta-tubulin. Residues 221, Thr to Ser, and 283, Ala to Ser, correspond in the bovine tubulin dimer structure to loops that most probably interact with other tubulin molecules within the microtubule, and might contribute to cold-adaptation of microtubules. 相似文献
918.
Maliarchuk Ba Wozniak M Czarny J Derenko MV Grzybowski T Miscicka-Sliwka D 《Molekuliarnaia biologiia》2007,41(1):3-7
The paper presents allele frequencies at 15 STR loci (D3S1358, vWA, FGA, TH01, TPOX, CSFIPO, D5S818, D13S317, D7S820, D16S539, D2Sl338, D8S1179, D21S1l, D18S51, D19S433), used in forensic medicine, in Russian sample (n = 176) representing population of the European part of the Russian Federation. The combined power of discrimination (PD) and the combined power of exclusion (PE) for the 15 STR loci were 0.999 999 999 999 999 986 and 0.999 999 331 310 171 000, respectively. The data obtained for allele and genotype frequencies conformed to Hardy-Weinberg expectations. According to the presented data, loci D2S1338, D18S51, D21Sll and FGA are the most informative markers for Russians. The data obtained may be used as reference database for forensic medicine laboratories in Russian Federation. 相似文献
919.
Conformational changes in human integrin alphaIIbbeta3 after platelet activation, monitored by FRET 总被引:1,自引:0,他引:1
Integrin alpha(IIb)beta(3), an abundant heterodimeric receptor at the surface of blood platelets, binds adhesive proteins after platelet activation and plays a primary role in haemostasis. In solution, it has been observed mainly in two conformations: the bent and the extended forms. Based on X-ray crystallography, electron microscopy and immunochemical observations of full-length integrin ectodomains and intact integrins, it has been agreed that unactivated integrins are in the bent conformation, both isolated in solution and in living cells. However, consensus is yet to emerge on the bent or extended conformation of activated integrins and on their mechanism of activation (the switchblade, the deadbolt and the S-S reduction models), which require further experimental tests at the cell level to become established facts. Here, we tested the proposed structural rearrangements undergone by integrin alpha(IIb)beta(3) after cell activation, by using F?rster-type fluorescence resonance energy transfer (FRET) and attached fluorescent labels to Fab fragments of monoclonal antibodies directed to the betaA domain of the beta(3) subunit (donor, Alexa488-P97 Fab) and to the Calf-2 domain of the alpha(IIb) subunit (acceptor, Cy3-M3 Fab or Cy3-M10 Fab). The FRET efficiencies observed after ADP or TRAP platelet activation changed less than 20% from the resting values, showing that the distance between the labeled Fab fragments changes only modestly after platelet activation by physiological agonists. This observation is consistent with a conformational model of the activated integrin in the cell less extended than in the switchblade model. 相似文献
920.
Pérez-Lara A Corbalán-García S Gómez-Fernández JC 《Archives of biochemistry and biophysics》2011,(1):36-41
Curcumin modulates the activity of protein kinase Cα (PKCα) when assayed in the presence of vesicles including phosphatidylcholine, phosphatidylserine and diacylglycerol. Increasing concentrations of curcumin progressively increased PKCα activity at concentrations lower than 20 μM, but at higher concentrations of curcumin the activity decreased although, at concentrations of curcumin of up to 100 μM the activity was always higher than the basal one (in the absence of curcumin). The maximum activity was reached at 3 μM curcumin, at 20 and 30 mol% of phosphatidylserine, 10 μM Ca2+ and 2 mol% diacylglycerol. The same type of modulation was observed when changing the concentration of phosphatidylserine, diacylglycerol and Ca2+. No effect of curcumin was found when the activity was assayed in the presence of Triton X-100 mixed micelles which included phosphatidylserine and diacylglycerol, indicating that the effect of curcumin was membrane-dependent. The pattern of binding of PKCα to membrane vesicles as a function of curcumin concentration closely correlated with the pattern of activating effect. It was concluded that the effect of curcumin on PKCα activity was related to its effect on the membrane, which may modulate the binding of the enzyme to the membrane. 相似文献